Conventionally, if an aspect ratio of a video signal is different from an aspect ratio of a display unit in displaying a video based on the video signal on the display unit, a screen size is adjusted by adding black strip regions on top and bottom or on right and left of the video. PTL1 describes a video converter that detects black strip regions on the basis of a brightness level of an input video signal and expands the video after removal of the black strip regions so as to display a video with no black strips on the display unit.